One type of high voltage field effect transistor (FET) is a heterostructure FET (HFET), also referred to as a high-electron mobility transistor (HEMT). HFETs based on gallium nitride (GaN) and other wide bandgap nitride III materials can be used with electrical devices in high-speed switching and high-power applications (such as power switches and power converters) due to their high electron mobility, high breakdown voltage, and high saturation electron velocity characteristics. These physical properties allow HFETs to change states substantially faster than other semiconductor switches that conduct the same currents at similar voltages. The materials used in the construction of HFETs also allow them to operate at higher temperatures than transistors that use traditional silicon-based technology.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.